fix broken test
fix broken test

donabrams/immutable-js,donabrams/immutable-js,PeterDaveHelloKitchen/immutable-js,maxehnert/immutable-js,facebook/immutable-js,Dashed/immutable-js,donabrams/immutable-js,maxehnert/immutable-js,PeterDaveHelloKitchen/immutable-js,facebook/immutable-js,Dashed/immutable-js,facebook/immutable-js,facebook/immutable-js,maxehnert/immutable-js,Dashed/immutable-js,maxehnert/immutable-js,PeterDaveHelloKitchen/immutable-js